In　this　paper,　the　influences　of　backwashing　conditions　on　the　washing　efficiency　(P)　were　systematically　investigated　by　a　combination　of　orthogonal　table　and　multivariate　linear　regression　methods.　The　experiments　were　performed　with　the　feed　suspension　from　SBR　and　deionized　water　in　laboratory-scale　dead-end　microfiltration　test　unit　with　0.1　mu　m　PES　microfiltration　membrane.　The　impact　of　shearing　stress　on　the　backwashing　recovery　(r(i)),　and　mass-transfer　coefficient　on　washing　efficiency　(P)　were　studied　respectively.　The　results　showed　that　backwash　and　water　rinsing　introduced　membrane　filtration　process　could　restore　the　declined　flux　close　to　100%.　However,　the　ability　of　backwashing　was　gradually　reducing　with　the　increase　of　backwashing　cycle,　which　was　associated　with　the　increasing　accumulation　of　irreversible　fouling　onto　and　into　the　membrane　pores.　r(i)　and　P　increased　with　the　increase　of　transmembrane　pressure　(TMP),　and　decreased　with　the　increase　of　operating　temperature.　Since　the　foulants　are　more　susceptible　to　be　washed　away　from　the　membrane　pores　during　a　longer　backwash,　the　r(i)　got　a　high　value,　on　the　contrary,　the　productivity　decreased　with　an　increase　of　backwash　duration　due　to　the　back　pumping　of　more　detergent.　The　average　contribution　of　backwashing　conditions　on　P　were　detergent　temperature　(50.49%)＞　transmembrane　pressure　(39.84%)＞　backwashing　times　(7.27%)＞　backwashing　time　(2.39%).　The　backwashing　conditions　were　optimized　and　the　relationship　between　backwashing　conditions　and　washing　efficiency　(P)　was　analyzed　and　defined　quantitatively.　(C)　2011　Elsevier　B.V.　All　rights　reserved.